Thread-cutting mechanism for sewing-machines.



No. 737,122. v PATENTED AUG. 25,1903;

I v RI Ll THREAD CUTTING MECHANISM FOR SEWING, MACHINES,

. APPLIOATIOH IILBD norm, 1901. I no xonnL. 4 8HEETB-BHI1ET 1.

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PATENTED AUG. 25, 1903.

I R. L. LYONS. THREAD CUTTING MECHANISM FOR SEWING MACHINES.

APPLIO Q ATION-IILBD NOV. 14, 1901.

H0 MODEL.

BATENTED AUGQ25, 1903."

. R. L. LYONS. THREAD CUTTING MECHANISM FOR SEWING MACHINESr.APPLIOATION FILED NOV. 14, 1901.

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.PATENTED AUG. .25; 1903.

v No.y'737,122.

i R.'L. LY0NS.,

THREAD GUTTING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED NOV. 14, 1901- 4 E lHEET8-SHEET 4.

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PATE T- OFFICE.

ROBERT L. LYONS, OF BOSTON, MASSACHUSETTS.

THREAD-CUTTING MECHANISM 'FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 737,122, dated August25, 1903.

Application filed November 14,1901. Serial No. 82,234. N model To aZZwhom it may concern.-

Be it known that 1, ROBERT L. LYoNs, of Boston, in the county of Suffolkand State of Massachusettahave invented certain new and usefulImprovements in Thread-Cutting Mechanism for Sewing-Machines, of whichthe following is a specification.

This invention relates to sewing-machines having attachments for cuttingor severing the thread and gripping it so as to hold it in position fora newoperation. 4 1

The invention consists in certain novel featuresofconstructionandarrangementin such. machines, which I shall now proceedto describe and claim.

Of the accompanying drawings, Figure 1 represents a front elevation of asewing-machine constructed in accordance with my invention, the framebeing partly broken away.

Fig. 2 represents a plan view of the parts above the work-plate. 3 Fig.3 represents a similar View, ona reduced scale, with the parts in adifferent position. Fig. 4 represents a perspective view of the 'mainparts.

Figs. 5 and 6 represent end elevations showing the gripping devices indifferent positions. Fig. 7 represents a detail sectional view showingthe action of the grippers and-the aux-- iliary cutter on the thread.Fig. 8 is a-detail perspective view illustrating principally the actionof the cutting and holding device for the underthread. Fig. 9 is across-section of the gripping-jaws. Fig. 10 is a vertical section on theaxis of the'cam-shaft which operates the grippers. 1 The same referencecharacters indicate the same parts in all the figures.

In the drawings, 1 is the arm; 2, the workplate; 3, the needle-bar; 4,the needle; 5, the presser-bar, and in Fig. 1 6 represents thestitch-forming mechanism below the workanism for severing and holdingthe upper thread is adapted after a certain number of stitches have beenformed to automatically moveforward in position to cut and grip the,thread between the needle and the work, whereby the necessity on thepart of the operator for performing this operation isdone away with, andthe upperthread is properly held in position for a new operation. Myimprovements also have provisions whereby soon'after the stitching ofthe new button has begun the grippers which hold the end.

of the starting-thread are caused to retract and draw said end acrossthe edge of a cutter, whereby this end is severed close to the work.

11 12 are a pair of gripping-jaws pivoted together at 13, the rearmostand under jaw 11 having a cutter- 14, Fig. 9, adapted to coact with theunder side of the jaw 12, the arrangement being such that when the jawsare brought together upon the thread the thread is severed and thesevered portion held or gripped between the ends of the jaws. The jaw 11is carried by a slide 15, and the jaw '12 is mounted upon the jaw 11.The slide'15 -iscarried in guides on a slide-holder l6,which isjournaled to rock on pivots 17 17 and supported by a vertical sleeve 18,projecting upwardly from the work-plate or bed of the machine, the angleof said holder, and hence the degree of elevation of the jaws above thework-plate, being regulated by an adjusting device 19. The sleeve 18journals a vertical shaft 20, having on its lower end a gear 21,engaging a worm 22 on the under shaft 23 of the'machine, which operatesthe lower part of the stitching mechanism. The upper end of the shaft 20carries a snail-cam 24, which acts on a stud 25, on the slide 15,whereby. the gripping-jaws are projected toward the stitchformingmechanism. A spring 26 retracts the jaws. A second spring 27 normallycloses the jaw 12 into gripping relation with the jaw '11,-and a secondcam 28, mounted above cam 24, acts on the heel of jaw 12, so as toopenthe same into position to engage the thread.

The upper cam 28 is held to the lower cam 24 by a screw 29, passingthrough a slot 30 in cam 28, whereby the upper cam mayberotatably'adjusted so as to cause the release of the jaw 12 to occurwhile the needle is elevated. While the machine. is stitching the buttonon the fabric the jaws 11 12 are moved forward by the cam 24 from aretracted position toward the stitching mechanism, and during suchmovement they are held open by the cam 28, so as to pass on oppositesides of the path of the needle. The release of the jaw 12 by its cam 28allows the spring 27 to act to carry the gripping portion of jaw 12toward the gripping portion of jaw 11; but provision is made forarresting this movement by means of a pivoted stop-dog 31 normally inthe path of the jaw 12, which holds the jaws temporarily innearly-closed relation, as shown in Fig. 5. A link 32 connects the dog31 with a pivoted lever 33, having a chain 34 connecting it with asuitable treadle, whereby the operator is enabled to lift the dog 31 atwill and release the jaw 12. Thus if through any faulty adjustment ofthe machine jaw 12 should be released by its cam 28 while the needle 4is down between the jaws the operator may continue the machine inoperation until the needle is elevated and may then release the jaw 12.The release of the jaw 12 by the elevation of the dog 31 brings ittogetheinupon the jaw 11, and the thread is thereby severed close to thework, and the severed end is gripped and held by the jaws to the rear ofthe path of the needle. The machine is thus maintained in condition fora new operation without the operator being required to touch the thread.

35 is a relatively fixed cutter having its cutting edge 36 above thework-plate and below the jaws 11 12 a slight distance to the right ofthe path of the needle. The machine is arranged so that the jaws ll 12remain stationary for a while after the machine has been started on anew button, the end of the starting-thread being held to the rear of theneedle while several stitches are taken, after which the stud 25 on theslide 15 escapes over the abrupt corner 37 of the cam 24 and the spring26 retracts the jaws 12. This causes the thread to be carried across theedge of the cutter 35, as represented in Fig. 7, whereby the thread endis severed close to the button and the short loose end of thread whichremains on the button is laid in with the succeeding stitches.

The knife 14 of the thread-gripping device may be omitted, if desired,so that the thread is not cut when the grippers 11 12 come together, butis broken between the grippers and the work by the act on the part ofthe operator of withdrawing the work.

I claim 1. In a sewing-machine, the combination of stitch-formingmechanism, means to automatically grip and hold the thread out of thepath of the needle after a predetermined number of stitches have beenformed, and means to automatically sever the held thread end after oneor more succeeding stitches have been formed.

2. In a sewing-machine, the combination of stitch-forming mechanism, athread-gripping device, means under the control of the operator toarrest the thread-gripping action of said device, and means toautomatically bring said device into coacting relation with said means.

3. In a sewing-machine, the combination of stitch-forming mechanism, apair of coacting grippers one of which is capable of anopening-and-closing movement with respect to the other, a spring deviceto yieldingly close said movable gripper, a cam adapted to open and thenrelease said gripper, and a stop under the control of theoperatoradapted to arrest the closing of said gripper after its release by thecam and movable to release the gripper.

4. In a sewing-machine, the combination of stitch-forming mechanism, theunder shaft for operating the lower part of said mechanism, ahorizontally-moving slide mounted above the work-plate, thread-gripperscarried by said slide, a vertical shaft geared to said under shaft, andtwo cam devices carried by said vertical shaft, one of said cam devicescontrolling the movement of said slide and the other controlling therelative openingand-closing movement of the grippers.

In testimony whereof I have affixed my signature in presence of twowitnesses.

ROBERT L. LYONS.

